Apparatus for transporting webs of photosensitive material through developing machines or the like

ABSTRACT

A developing machine for webs of photosensitive material wherein a band is trained over a set of guide rolls and can transport a separable clamp through a series of vessels containing developing, fixing and other liquids. A portion of the clamp extends sideways from the band and has a set of mushroom-, pinor barb-shaped projections which are caused to penetrate through the leader of a web so that the latter is entrained through the developing machine. The projections can be attached to the leader outside or in the interior of the machine by causing the leader and the clamp to pass between two rollers one of which is grooved to receive the projections and is sufficiently close to the other roller to cause the projections to puncture the leader. The leader is folded over the clamp to reduce the strain on the punctured portions.

United States Patent 1191 Kwiaikowski et al.

[22] Filed:

[ APPARATUS FOR TRANSPORTING WEBS OF PHOTOSENSITIVE MATERIAL THROUGH DEVELOPING MACHINES OR THE LIKE [75] Inventors: Wolfgang Kwiaikowski,

Unterhaching; Milovan Vidakovic; Horst Kempe, both of Munich, all of Germany [73] Assignee: Agfa-Gevaert Aktiengesellschaft,

Leverkusen, Germany Mar. 15, 1973 21 App]. No.: 341,606

[30] Foreign Application Priority Data 3,619,050 ll/l97l Swanke 226/92 X May 14,1974

2,928,329 3/1960 Limbach ..226/92X Primary Examiner-Allen N. Knowles [57] ABSTRACT Adeveloping machine for webs of photosensitive material wherein a band is trained over a set of guide rolls and can transport a separable clamp through a series of vessels containing developing, fixing and other liquids. A portion of the clamp extends sideways from the band and has a set of mushroom-, pinor barb-shaped projections which are caused to penetrate through the leader of a web so that the latter is entrained through the developing machine. The projections can be attached to the leader outside or in the interior of the machine by causing the leader and the clamp to pass between two rollers one of which is grooved to receive the projections and is sufficiently close to the other'roller to cause the projections to puncture the leader. The leader is folded over the clamp to reduce the strain on the punctured portions.

23 Claims, 9 Drawing Figures APPARATUS FOR TRANSPORTING WEBS OF PHOTOSENSITIVE MATERIAL THROUGH DEVELOPING MACHINESOR THE LIKE BACKGROUND OF THE INVENTION The present invention relates to apparatus for transporting webs of flexible material, and more particularly to improvements in apparatus for transporting webs of photosensitive material through developing, fixing, rinsing and/or like stations.

It is already known to transport webs of photosensitive material through a developing machine by resorting to an endless band which is trained around rolls and carries a laterally extending entraining device in the form of a clamp. That portion of the clamp which extends beyond the band is formed with an elongated slot which is wide enough to receive the leader of a web of photosensitive material. The leader is introduced into the slot and is thereupon convoluted around the clamp to prevent its detachment while the band is in motion to transport the web through a developing, fixing, rinsing and/or other station. The convolutions of the leader around the clamp form a pocket which is filled with developer during transport of the clamp through the developing station. As a rule, it takes a certain amount of time before the liquid which is entrapped between the convolutions of the leader can escape back into the vessel for developing liquid. If the film is treated in several successive stages, i.e., if the web is to enter seriatim a succession of closely adjacent vessels, substantial amounts of developing liquid are lost due to transfer of such liquid into the vessel following the vessel which contains developing liquid. Also, the developing liquid which is carried along in the pocket around the clamp is likely to affect the concentration and/or other characteristics of liquid in the next-following vessel. A further drawback of such transporting apparatus is that the leader of a web must be attached to the clamp by hand, normally in a dark room.

SUMMARY OF THE INVENTION An object of the invention is to provide a novel and improved apparatus for transporting webs of photosensitive material or the like through one or more processing stations.

Another object of the invention is to provide the apparatus with novel means for automatically attaching the leader of a web to an entraining device which serves to transport the web along a predetermined path extending through one or more processing stations.

A further object of the invention is to provide the transporting apparatus with an entraining device which can safely engage and advance a web without the foroping or like machines. The apparatus comprises a conveyor defining an elongated path (preferably an endless path), drive means which is operative to move the conveyor, and a novel entraining device which is secured to the conveyor and has one or more projections adapted to penetrate through the leader of a web whereby the device entrains the web in response to operation of the drive means. The entraining device preferably comprises a first portion which is separably connected to the conveyor (the latter preferably comprises an endless flexible element in the form of a chain, band or rope) and a second portion which cxtends sideways from the conveyor and carries one or more projections, preferably a row of projections which can be staggered with respect to each other, as considered in the direction of travel of the entraining device. When the leader of a web is attached to the projections on the second portion of the entraining device, the web is transported along the elongated path by moving adjacent to the flexible element of the conveyor.

The projections can resemble mushrooms, barbs, rivets, cylindrical pins, pins with pointed heads or the like.

The apparatus preferably further comprises an automatic or semiautomatic attaching unit for securing the leader of a web to the projections. It is also desirable to fold the leader of the web over the second portion of the entraining device to thus reduce the likelihood of tearing of the leader in the region where the leader is punctured by the projections while the entraining device pulls the web through one or more processing stations. Such folding produces some friction between the leader and the entraining device and thus protects the punctured portion of the leader from excessive tensional stresses when the flexible element of the conveyor is in motion.

The leader can be connected with the flexible element by two or more identical or different entraining devices.

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved transporting apparatus itself, however, both as to its construction and its mode of operation, together with additional features and advantages thereof, will be best understood upon perusal of the following detailed description of certain specific embodiments with reference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a fragmentary vertical sectional view of a developing machine for photosensitive material which embodies one form of the improved web transporting apparatus;

FIG. 2 is an enlargedview of the automatic web attaching unit as seen in the direction of arrows from the line IIII of FIG. 1;

FIG. 3 illustrates a portion of the machine shown in FIG. I, turned through and with the entraining device about to engage the leader of the web;

FIG. 4 illustrates the structure of FIG. 3 but with the leader of the web connected to the entraining device;

FIG. 5 is an enlarged side elevational view of the entraining device;

FIG. 6 is a plan view of the entraining device;

FIG. 7 is a fragmentary side elevational view of a second entraining device;

FIG. 8 is a sectional view as seen in the direction of arrows from the line VIII-VIII of FIG. 7; and

FIG. 9 is a side elevational view of a modified attaching unit.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIG. 1, there is shown a portion of a machine for development and other treatment of here shown as a band or belt which is trained over a 1 numer of guide rolls 3, 4, 5, 7 and 8. The rolls 3, 4 and 5 define a portion of the path for the band 6 and such portion of the path extends into and from the vessel 2 so that a web 19 which is being pulled by the band 6 is treated by liquid during travel from the roll 3 toward the roll 5. Additional rolls (not shown) are provided to guide the band 6 along additional portions of the endless path which additional portions extend through supplies of liquid in the additional vessels of the developing machine. The rolls 7 and 8 guide the band 6 along a vertical portion of the endless path wherein the band travels upwardly behind an aperture la in the housing 1. The band 6 preferably consists ofa synthetic plastic material which is capable of resisting the action of chemical substances in the vessel or vessels 2. The housing 1 provides a light-tight enclosure around those portions of the endless path wherein the web 19 is still sensitive to light.

The aperture la is located upstream of a second aperture 1b which is provided in the top wall of the housing 1 and can be sealed by the casing of a cassette or magazine 12 for a roll 12b of convoluted web 19. The casing of the cassette 12 has an opening 12a through which the web 19 can be withdrawn to pass through the aperture lb and thereupon along the path defined by the conveyor including the band 6 and guide rolls 35 and 7-8. The drive means for the band 6 includes a suitable motor (not shown) and a shaft which drives one of the guide rolls for the belt (see the drive shaft 7a for the guide roll 7).

The aperture la in the front wall of the housing 1 is long and wide enough to allow for attachment to the band 6 of a specially designed entraining device or clamp 11 which can be attached to the leader 19a of the web 19 and serves to drag the web 19 through the developing machine and back to the aperture 1a so that the treated web can be detached from the clamp 11 and withdrawn from the housing 1. The details of the improved clamp 11 are illustrated in FIGS. 5 and 6. The manner in which the clamp 11 can be separably connected with the band 6 forms no part of the present invention; it suffices to say that the clamp must adhere to the band with a force which suffices to insure that the web 19 will be withdrawn from the cassette 12 when the leader 19a is secured to the clamp and the band is in motion in the direction indicated by arrow 18.

The path for successive increments of the band 6 between the apertures la and lb of the housing 1 extends through the mouth of a light trap which includes two brushes 9, located immediately upstream of the guide roll 8 and having flexible bristles which yield when engaged by the clamp 11. The illustrated light trap can be replaced with any other suitable light trap (for example, by a labyrinth seal), as long as it is capable of preventing the entry of light into that portion of the interior of the housing 1 which is adjacent to the upper aperture 1b. 1

The size of the aperture lb preferably approximates or-is slightly less than theoutline of the bottom panel of the cassette 12 so that, when the cassette is properly placed onto the top wall of the housing 1, it seals the aperture lb against entry of light into the interior of the housing. To this end,the top wall of the housing around the aperture lb can be lined with a suitable lightintercepting material, such as a gasket consisting of opaque sponge rubber. The gasket prevents penetration of light into the housing 1 (by way of the aperture lb) even if the dimentions of the cassette l2 deviate from the norm and/or if the cassette is not placed into an optimum position with respect to the housing.

The aperture lb is located at the upper end of a funnel-shaped guide 13 wherein the leader 19a of a web 19 can be advanced toward and through the nip of two idler rollers l4, l5 and into abutment with a fixed stop 17 in the interior of the housing 1. The guide 13 may consist of rigid or yieldable material and is secured to the inner side of the top wall of the housing. The leader 19a of the web 19 is withdrawn through or extends from the opening 12a of the cassette l2 and is introduced into the aperture 1b and guide 13, nip of the rollers 14, 15 and into abutment with the stop 17 before the cassette 12 is deposited on the aforementioned opaque liner surrounding the aperture 1b.

The roller 15 is mounted at a level above a third roller 16 whose configuration is shown in FIG. 2. In the illustrated embodiment, the roller 16 has a cylindrical peripheral surface provided with a number of circumferential recesses for portions of elastic rings which define a number of circumferential grooves 16b. The grooves 16b are equidistant from each other, as considered inthe axial direction of the roller 16.

The roller 16 is an idler roller; however, it is also possible to provide the apparatus with drive means for rotating the roller 15 and/or 16 at a peripheral speed which corresponds to the speed of lengthwise movement of the band 6. If desired, the roller 16 can be replaced with a roller having a smooth cylindrical peripheral surface which is provided with recesses replacing the circumferential grooves 16b between the rings 16a ofthe roller 16 shown in FIG. 2. The rollers 15, 16 constitute two members of an automatic attaching unit which can connect the leader 19a of a web 19 to the clamp 11 in response to transport of the clamp through the passage between the rollers l5, 16. The distance between the axes of the rollers 15 and 16 is fixed and the minimum width of the passage between these rollers preferably equals the thickness of the clamp 11 plus twice the thickness of the web 19. It will be noted that the lower roller 16 is slightly offset with reference to the upper roller 15 so that the leader 19a which abuts against the stop 17 contacts the periphery of the roller 15 but need not contact the rings 16a of the roller 16. The emulsion-coated side of the web 19 is assumed to be that side which faces the roller 15, Le, which faces away from the roller 14 when the leader 19a abuts against the stop 17. Once the web 19 advances to and beyond the guide roll 3, the latter cooperates with the roller to maintain the web out of contact with the roller 16.

The construction of the entraining device or clamp 11 is shown in FIGS. 5 and 6. This clamp comprises a first portion 11A which is provided with U-shaped extensions lla, 11b serving to engage the marginal portions of the band 6 and to thus secure the clanip to the band. A second portion 110 of the clamp ll extends sideways from the band 6 in the channel between the extensions Ila, 11b and is provided with at least one row of specially configurated projections 11d which can penetrate through the leader l9a to thus indirectly secure the leader 19a to the band 6 so that the web 19 shares the lengthwise movement of the band through the vessel 2, through one or more additional vessels, and thereupon toward the aperture la in the housing 1. The channel between the extensions 11a, 11b is preferably somewhat narrower than the band 6 so that the latter is engaged by the extensions 1 1a, 1 1b with sufficient friction to avoid slippage of the clamp 11 relative to the band while the clamp moves through the passage between the rollers 15 and I6 and its projections lld are caused to puncture the leader 19av Each of the projections 11d resembles a mushroom, i.e., it comprises a stem or shank 1 1e which is rigid with the portion 11c and a substantially semispherical head llfbest shown in FIG. 5. When the head llfpenetrates through the leader 19a, the latter surrounds the respective shank lle and cannot be detached from the respective projection 11d except by the exertion of a force which normally equals or approximates the force necessary to tear the leader 19a. Each projection 11d can be said to constitute a barb which can be caused to penetrate through the leader 190 but cannot be readily withdrawn without destroying the leader. As shown in FIG. 6, the projections lld are equidistant from each other, as considered in a direction at right angles to the direction of movement of the band 6 (arrow 18 in FIG. I) but can be staggered with respect to each other as considered in the direction of the arrow 18. This reduces the likelihood of complete destruction of the leader 19a during attachment of the clamp 11 because the points where the projections 11d puncture the web are not located at the same distance from the front 1 edge face of the leader. The distance between the axes of neighboring projections lld (as considered at right angles to the direction indicated by the arrow 18) equals the distance between the centers of neighboring grooves 16b between the rings 16a of the roller 16.

The mode of automatically attaching the leader 19a ofa web 19 to the clamp 11 is illustrated in FIGS. 3 and 4. It is assumed that the clamp 11 has been secured to the band 6, namely, to that portion of the band which is accessible by way of the aperture la in the housing I. It is further assumed that the leader 19a of the web 19 shown in FIG. 1 has been threaded through the opening 12a of the cassette 12, through the aperture lb and guide 13, through the nip of the roller l4, l5, and that its front edge face abuts against the stop 17. The emulsion-coated side of the leader 19a faces the roller 15 and the leader is out of contact with the grooved roller 16. When the motor which drives the shaft 7a is started, the band 6 begins to move in the direction indi- 6 cated by the arrow 18 and causes the clamp 11 to pass between the brushes 8, 9 of the light trap, to travel around the guide roll 8 and to thereupon advance toward the passage between the attaching rollers 15, 16. While the clamp 11 travels between the guide rolls 8 and 3, its projections lld are located at the underside of the portion 110. Each such projection lld is aligned with one of the grooves 16b which grooves constitute wider portions of the passage between the attaching rollers l5, 16. i

As the clamp ll advances toward the rollers 15, 16, the leading edge 11g of its portion engages the leader 1% (which abuts against the stop 17) and folds the leader in a manner as shown in FIG. 4. This creates at least some friction between the leader and the clamp. The clamp 11 thereupon enters the passage between the rollers 15, 16 whereby the rings 16a of the roller 16 cooperate with the upper roller .15 to cause the projections 11d to puncture the leader 19a (namely, the front portion 19a of the leader) so that the heads 11f penetrate through the material of the portion 19a with the result that the punctured portion 19a surrounds the shanks lle and cannot be readily detached from the clamp, As mentioned before, the projections 11d pass through the grooves 16b and the narrowest portion of the passage between the attaching rollers 15, 16 (Le, between the periphery of the roller 15 and the peripheral surfaces of the rings 16a) is just wide enough to provide a path for the clamp 11 and the folded portions 19a" of the leader 19a. The crease between the portions 19a, 19a" overlies the leading edge 11g of the portion 110. The friction between the portions l9a, 19a and the clamp portion 11c is considerable and suffices to counteract some of the tensional stresses upon the web 19 so that the leader 19a is not likely to tear in the region of the projections lld. In other words, the web 19 is entrained by the band 6 due to penetration of projections 11d through the portion 19a of the leader 19a and to a large extent (preferably greater extent) as a result of friction between the portions 19a, 19a" of the leader and the portion 110 of the clamp 11. The leader 19a is likely to tear if the material of the web is moist; therefore, the folding of the leader around the clamp 11 constitutes a desirable (but optional) feature which reduces the likelihood of damage to the leader during automatic attachment of the web to the band 6 as well as during lengthwise transport of the web through the developing machine. When traveling in the direction of the arrow 18, the web is adjacent to one marginal portion of the band 6.

If the material of the web 19 is such that it offers a substantial resistance to penetration of projections 11d through the leader 19a, the attaching unit preferably employs two relatively large rollers l5, 16 to thus insure that the penetration takes place during travel of the clamp 11 along a relatively long portion of the path which is defined by the conveyor including the band 6. In other words, the diameters of the rollers l5, 16 are proportional to the resistance which the leader of a web offers to puncturing by the projections 11d. This insures that the band 6 need not pull the clamp 11 with a great force while the projections 11d puncture the leader 19a. It is also possible to positively drive at least one of the rollers l5, 16 so as to further reduce the force which must be furnished by the band 6 in order to advance the clamp 11 through the passage between the attaching members. FIG. 4 illustrates schematically a drive means 116 for the shaft 16d of the grooved attaching roller 16. The drive means 116 insures that the band 6 and/or the web 19 need not rotate the rollers l5, 16 during attachment of the leader 19a to the projections 11d; on the contrary, the rollers I5, 16 supply a pulling force which causes the clamp 11 to pass therebetween.

It is further possible to replace the illustrated attaching means with a stationary attaching structure of the type shown in FIG. 9. Thus, two blocks 215, 216 are disposed at the opposite sides of the path for the band 6 and define a wedge-like passage 250 whose width diminishes in the direction of the arrow 18. The surfaces 251, 252 bounding the passage 250 are smooth so as to offer little resistance to the travel of the band 6, leader 19a (not shown) and clamp 11 (not shown). One of the surfaces 251, 252 is formed with grooves 253 cor-responding to the grooves 161) and serving to receive the projections 11d of the clamp while the clamp travels between the blocks 215, 216.

The operation of the developing machine shown in FIG. 1 will be readily understood upon perusal of the preceding description. As a rule, the leader 19a will extend from the casing of the cassette 12 (opening 12a) before the cassette is placed onto the top wall of the housing 1 so as to seal the aperture lb. Such leader is threaded through the aperture 1d, guide 13 and the nip of the rollers 14, 15 so as to come into abutment with the stop 17. The attachment of the leader 19a to the clamp 11 thereupon proceeds automatically as soon as the clamp is secured to the band 6 and the latter begins to move in the direction indicated by the arrow 18. The band 6 is arrested when the clamp 11 returns into the space behind the aperture la so that the leader 19a of a treated web 19 can be forcibly detached from the projections 11d and secured to the core of a collecting spool (not shown). The clamp 11 remains attached to the band 6 and is ready to be connected with the leader 19a of the next-following web.

An important advantage of the improved attaching unit is that it can secure a relatively short stretch of the leader 19a to the clamp 11 without risking that the leader would become detached during transport through the developing machine. This is desirable because the leader is often very short, i.e., it is immediately followed by light-sensitive portions of the web. For example, the length of the web portion between the opening 12a and the stop 17 need not exceed a few centimeters, i.e., less than the customary length of the leader on a roll of photographic film or exposed photographic paper. When the cassette 12 is mounted on the housing 1 in the manner shown in FIG. 1, the chamber 1A of the housing is completely sealed from light because it has only two openings, namely, the aperture 1a in the top wall of the housing and the passage defined by the brushes 8, 9 of the light trap downstream of the aperture 1a. It will be noted thatthe attachment of the leader 19a to the clamp 11 takes place in a dark portion (chamber 1A) of the housing 1.

FIGS. 7 and 8 illustrate a portion of a modified clamp 11] having different projections 111d (only one shown). The head lllf of the projection 111d is located at the outer end of a shank llle and resembles a truncated hemisphere having a convex peripheral or outer surface 111p and two substantially parallel side faces 111r. An advantage of the projection 111d is that 1 8 it can be readily produced from synthetic plastic material in an .injection molding machine.

It is also within the purview of the invention to provide a clamp with projections ofcylindrical outline, i.e., each projection merely comprises a pin-shaped shank or stem without any head at the outer end of the shank. It is advisable to provide such cylindrical projections with a slightly convex top face. The leader is not likely to become separated from a cylindrical pin-shaped projection as long as the web is under at least some tension during travel through the developing machine. As a rule, the web is under constant tension during travel through the developing machine so that the separation of its leader from cylindrical or pin-shaped projections is highly unlikely. Furthermore, the aforediscussed friction between the portions 19a, 19a" of the leader 19a and the portion of the clamp 11 also contributes to prevention of separation of the leader from the projections even if the projections do not have pronounced heads.

As mentioned before, the projections 11d of the clamp 11 shown in FIG. 1 are located at the underside of the portion 110 during travel below the roller 14. This is desirable because the projections 11:! do not come in contact with the roller 15 and roll 4, i.e., with those parts which contact the emulsion-coated side of the web 19. The projections 11d can contact the rolls 3 and 5 which, however, engage only the uncoated side of the web. That surface of the portion 110 which faces away from the projections 11d is preferably smooth and flat so that it cannot scratch or otherwise deface or damage the peripheral surface of the roller 15 and/or guide roll 4.

It is further within the purview of the invention to provide an attaching unit which is located outside of the chamber 1A of the housing 1 and can be manipulated by hand to attach the leader 19a of a web 19 to the projections 11d of a clamp 11, for example, before the clamp is connected to the band 6. The just discussed attaching unit may resemble a splicer or stapler which can receive the leader of a web and the portion 110 ofa clamp 11 and has a movable portion which can be displaced to thereby force the projections through the material of the leader. The manually operated attaching device may include the block-shaped attaching members 215, 216 of FIG. 9 and a handle which is actuatable to move the member 215 toward the member 216 and/or vice versa. The clamp 11 which has been connected with a leader 19a is thereupon removed from the attaching unit and is connected to the portion of the band 6 behind the aperture la.

It is clear that the housing 1 need not be light-tight if it is mounted in a dark chamber, i.e., such housing can dispense with the outer wall which defines the apertures 1a, 1b and with the light trap 8, 9. Itis further possible to mount the band 6 in such a way that it need not be coplanar with an attached web 19. This can be achieved by using rollers and rolls having smaller-orlarger diameter portions for the band 6 and larger-orsmaller diameter portions for the web. Such type of conveyor will be used with specially designed clamps. Also, the band can be trained over a first set of rolls and the web can be guided by a discrete second set of rolls. Finally, the band 6 can be replaced with a cable, cord, rope, chain or another suitable endless flexible element.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features which fairly constitute essential characteristics of the generic and specific aspects of our contribution to the art and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the claims.

What is claimed as new and desired to be protected by Letters Patent is:

1. Apparatus for transporting webs of photosensitive material or the like, particularly for transporting photosensitive material through developing or like machines, comprising a conveyor defining an elongated path; drive means operative to move said conveyor; and an entraining device secured to said conveyor and having at least one projection means fixedly secured to the surface of said entraining device and adapted to puncture and at least partially penetrate through the leader of a web whereby said device entrains the web along said path in response to operation of said drive means.

2. Apparatus as defined in claim 1, wherein said conveyor comprises an endless flexible element and said entraining device comprises a first portion secured to and a second portion extending laterally from said flexible element, said entraining device having a plurality of projections provided on said second portion thereof.

3. Apparatus as defined in claim 2, wherein each of said projections has a rounded tip.

4. Apparatus as defined in claim 1, wherein said projection is a mushroom-shaped stud.

5. Apparatus as defined in claim 1, wherein said projection includes a shank and a substantially semispherical head which is arranged to penetrate through the leader of a web so that the leader thereupon surrounds said shank.

6. Apparatus as defined in claim 1, wherein said projection includes a shank and a head having a convex outer surface and two substantially parallel side faces, said head being arranged to penetrate through the leader of a web so that the leader thereupon surrounds said shank.

7. Apparatus as defined in claim 1, wherein said entraining device includes a first portion secured to and a second portion extending laterally from said conveyor, said entraining device having a plurality of projections provided on said secondportion thereof, said projections forming at least one row which extends transversely of said path and the projections of said row being equidistant from each other.

8. Apparatus as defined in claim 7, wherein the projections of said row are staggered with respect to each other, as considered in the direction of movement of said entraining device with said conveyor.

9. Apparatus as defined in claim 1, further comprising attaching means for forcing said projections into and through the leader of a web.

10. Apparatus as defined in claim 9, wherein said attaching means comprises a pair of attaching members disposed opposite each other at the opposite sides of a portion of said path and defining a passage for said entraining device and for the leader of a web, said passage having a narrower portion and a wider portion for said projection whereby, when the leader of a web is introduced into said passage while said entraining device is caused to move through said passage, said attaching members cause said projection to penetrate through the leader in said passage.

11. Apparatus as defined in claim 10, wherein said attaching members are rollers, one of said rollers having a circumferential groove defining said wider portion of said passage.

12. Apparatus as defined in claim 11, wherein said one roller has a cylindrical peripheral surface and said groove is provided in said peripheral surface.

13. Apparatus as defined in claim ll, wherein said one roller comprises two rings consisting of elastomeric material and flanking said circumferential groove.

14. Apparatus as defined in claim 11, wherein the axes of said rollers are located at a fixed distance from each other and the width of the narrower portion of said passage equals the thickness of said entraining device minus said projection plus twice the thickness of a web.

15. Apparatus as defined in claim 14, wherein said conveyor further comprises guide means for a web which is attached to said entraining device, said guide means being arranged to maintain a web, whose leader is attached to said projection, in contact with the periphery of one of said rollers.

16. Apparatus as defined in claim 11, wherein the diameters of said rollers are proportional to the resistance which the leader of a web offers to the penetration of said projection.

17. Apparatus as defined in claim 11, further comprising means for rotating at least one of said rollers.

18,- Apparatus as defined in claim 1, wherein said projection extends from one side of said entraining device and further comprising a source of convoluted web located at the other side of said entraining device.

19. Apparatus for transporting webs of photosensitive material or the like, particularly for transporting photosensitive material through developing or like machines, comprising a conveyor defining an elongated path, including an endless flexible element, drive means operative to move said conveyor, an entraining device secured to said conveyor defining an endless path by said endless flexible element, and having at least one projection which is adapted to puncture and at least partially penetrate through the leader of a web whereby said device entrains the web along said path in response to operation of said drive means, a housing at least partially surrounding said endless path, attaching means provided in said housing and operative to at tach the leader of a web to said entraining device, said housing having an aperture located upstream of said attaching. means, as considered in the direction of travel of said entraining device along said path, to afford access to said entraining device.

20. Apparatus as defined in claim 19, wherein said housing defines a light-tight chamber for said attaching means and further comprising a light trap provided in said housing for the passage of said entraining device from the region of said aperture into said chamber.

21. Apparatus as defined in claim 20, wherein said light trap comprises a plurality of brushes.

22. Apparatus as defined in claim 20, wherein said housing has a second aperture affording access to said chamber adjacent to said attaching means and adapted to be sealed by a magazine for a supply of convoluted Web whose leader can be introduced into said chamber by way of said second aperture.

23. Apparatus as defined in claim 19, wherein said entraining device is separable from said conveyor and further comprising attaching means operable to cause said projection to penetrate through the leader of a web prior to connection of said entraining device to said conveyor. 

1. Apparatus for transporting webs of photosensitive material or the like, particularly for transporting photosensitive material through developing or like machines, comprising a conveyor defining an elongated path; drive means operative to move said conveyor; and an entraining device secured to said conveyor and having at least one projection means fixedly secured to the surface of said entraining device and adapted to puncture and at least partially penetrate through the leader of a web whereby said device entrains the web along said path in response to operation of said drive means.
 2. Apparatus as defined in claim 1, wherein said conveyor comprises an endless flexible element and said entraining device comprises a first portion secured to and a second portion extending laterally from said flexible element, said entraining device having a plurality of projections provided on said second portion thereof.
 3. Apparatus as defined in claim 2, wherein each of said projections has a rounded tip.
 4. Apparatus as defined in claim 1, wherein said projection is a mushroom-shaped stud.
 5. Apparatus as defined in claim 1, wherein said projection includes a shank and a substantially semispherical head which is arranged to penetrate through the leader of a web so that the leader thereupon surrounds said shank.
 6. Apparatus as defined in claim 1, wherein said projection includes a shank and a head having a convex outer surface and two substantially parallel side faces, said head being arranged to penetrate through the leader of a web so that the leader thereupon surrounds said shank.
 7. Apparatus as defined in claim 1, wherein said entraining device includes a first portion secured to and a second portion extending laterally from said conveyor, said entraining deviCe having a plurality of projections provided on said second portion thereof, said projections forming at least one row which extends transversely of said path and the projections of said row being equidistant from each other.
 8. Apparatus as defined in claim 7, wherein the projections of said row are staggered with respect to each other, as considered in the direction of movement of said entraining device with said conveyor.
 9. Apparatus as defined in claim 1, further comprising attaching means for forcing said projections into and through the leader of a web.
 10. Apparatus as defined in claim 9, wherein said attaching means comprises a pair of attaching members disposed opposite each other at the opposite sides of a portion of said path and defining a passage for said entraining device and for the leader of a web, said passage having a narrower portion and a wider portion for said projection whereby, when the leader of a web is introduced into said passage while said entraining device is caused to move through said passage, said attaching members cause said projection to penetrate through the leader in said passage.
 11. Apparatus as defined in claim 10, wherein said attaching members are rollers, one of said rollers having a circumferential groove defining said wider portion of said passage.
 12. Apparatus as defined in claim 11, wherein said one roller has a cylindrical peripheral surface and said groove is provided in said peripheral surface.
 13. Apparatus as defined in claim 11, wherein said one roller comprises two rings consisting of elastomeric material and flanking said circumferential groove.
 14. Apparatus as defined in claim 11, wherein the axes of said rollers are located at a fixed distance from each other and the width of the narrower portion of said passage equals the thickness of said entraining device minus said projection plus twice the thickness of a web.
 15. Apparatus as defined in claim 14, wherein said conveyor further comprises guide means for a web which is attached to said entraining device, said guide means being arranged to maintain a web, whose leader is attached to said projection, in contact with the periphery of one of said rollers.
 16. Apparatus as defined in claim 11, wherein the diameters of said rollers are proportional to the resistance which the leader of a web offers to the penetration of said projection.
 17. Apparatus as defined in claim 11, further comprising means for rotating at least one of said rollers.
 18. Apparatus as defined in claim 1, wherein said projection extends from one side of said entraining device and further comprising a source of convoluted web located at the other side of said entraining device.
 19. Apparatus for transporting webs of photosensitive material or the like, particularly for transporting photosensitive material through developing or like machines, comprising a conveyor defining an elongated path, including an endless flexible element, drive means operative to move said conveyor, an entraining device secured to said conveyor defining an endless path by said endless flexible element, and having at least one projection which is adapted to puncture and at least partially penetrate through the leader of a web whereby said device entrains the web along said path in response to operation of said drive means, a housing at least partially surrounding said endless path, attaching means provided in said housing and operative to attach the leader of a web to said entraining device, said housing having an aperture located upstream of said attaching means, as considered in the direction of travel of said entraining device along said path, to afford access to said entraining device.
 20. Apparatus as defined in claim 19, wherein said housing defines a light-tight chamber for said attaching means and further comprising a light trap provided in said housing for the passage of said entraining device from the region of said aperture into said chamber.
 21. Apparatus as defined in claim 20, wherein said light trap comprises a plurality of brushes.
 22. Apparatus as defined in claim 20, wherein said housing has a second aperture affording access to said chamber adjacent to said attaching means and adapted to be sealed by a magazine for a supply of convoluted web whose leader can be introduced into said chamber by way of said second aperture.
 23. Apparatus as defined in claim 19, wherein said entraining device is separable from said conveyor and further comprising attaching means operable to cause said projection to penetrate through the leader of a web prior to connection of said entraining device to said conveyor. 